CN114008540A - Alignment, overlay, alignment mark, method of manufacturing pattern forming apparatus, and method of manufacturing pattern mark - Google Patents
Alignment, overlay, alignment mark, method of manufacturing pattern forming apparatus, and method of manufacturing pattern mark Download PDFInfo
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- G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
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- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
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Abstract
A resonant amplitude grating mark has a periodic structure configured to scatter radiation (602) of wavelength λ incident (600) on an alignment mark. Scattering is mainly due to coupling of incident radiation into waveguide modes in the periodic structure. Effective refractive index (n) of each part of the periodic structurel，n2) And length (d)l，d2) Is configured to provide unit cells in a periodic directionOptical path length (n)1d1+n2d2) Said optical path length (n)1d1+n2d2) Equal to an integer multiple (m lambda) of the wavelengths present in the spectrum of the radiation. Effective refractive index (n) of these portionsl，n2) And length (d)l，d2) Is also configured to provide an optical path length (n) of the second portion in the periodic direction2d2) Said optical path length (n)2d2) From 0.30 to 0.49 times the wavelength present in the spectrum of the radiation.
Description
Cross Reference to Related Applications
This application claims priority from european application 19186248.1 filed on 7/15.2019 and european application 19186925.4 filed on 7/18.2019, which are incorporated herein by reference in their entirety.
Technical Field
The present disclosure relates to a marking, overlay target, and associated methods of aligning and determining overlay errors that may be used in the manufacture of devices, for example, by lithographic techniques.
Background
A lithographic apparatus is a machine that is configured to apply a desired pattern onto a substrate. Lithographic apparatus can be used, for example, in the manufacture of Integrated Circuits (ICs). A lithographic apparatus may project a pattern (also commonly referred to as a "design layout" or "design") onto a layer of radiation-sensitive material (resist) disposed on a substrate (e.g., a wafer), e.g., at a patterning device (e.g., a mask).
To project a pattern onto a substrate, a lithographic apparatus may use electromagnetic radiation. The wavelength of the radiation determines the minimum size of features that can be formed on the substrate. Typical wavelengths currently used are 365nm (i-line), 248nm, 193nm and 13.5 nm. Lithographic apparatus using Extreme Ultraviolet (EUV) radiation having a wavelength in the range 4-20nm (e.g. 6.7nm or 13.5nm) may be used to form smaller features on a substrate than lithographic apparatus using radiation having a wavelength of, for example, 193 nm.
Low-k 1 lithography can be used to process features having dimensions smaller than the classical resolution limit of the lithographic apparatus. In such a process, the resolution formula may be expressed as CD — k1 × λ/NA, where λ is the wavelength of radiation employed, NA is the numerical aperture of the projection optics in the lithographic apparatus, CD is the "critical dimension" (typically the smallest feature size printed, but in this case half pitch), and k1 is the empirical resolution factor. Generally, the smaller k1, the more difficult it is to reproduce a pattern on a substrate that is similar in shape and size to a circuit designer's plan for achieving a particular electrical function and performance. To overcome these difficulties, complex trimming steps may be applied to the lithographic projection apparatus and/or the design layout. These fine tuning steps include, for example and without limitation, optimization of NA, customized illumination schemes, use of phase shifting patterning devices, various optimizations of the design layout, such as optical proximity correction (OPC, also sometimes referred to as "optical and process correction") in the design layout, or other methods commonly defined as "resolution enhancement techniques" (RET). Alternatively, a tight control loop for controlling the stability of the lithographic apparatus may be used to improve the reproduction of the pattern at low k 1.
Accurate placement of patterns on a substrate is a major challenge in reducing the size of circuit components and other products that can be produced by photolithography. In particular, a challenge in accurately measuring already laid-up features on a substrate is the critical step in aligning successive layers of features when superimposed to be sufficiently accurate to produce a working device with high yield. Typically, in today's submicron semiconductor devices, the so-called overlay is achieved within tens of nanometers, and can be as low as a few nanometers in the most critical layers.
In lithographic processes, it is often desirable to make measurements of the created structures, for example for process control and verification. Various tools for making such measurements are known, including scanning electron microscopes, which are often used to measure Critical Dimension (CD), and specialized tools for measuring overlay, the alignment accuracy of two layers in a device. Recently, various forms of scatterometers have been developed for use in the field of lithography. These devices direct a beam of electromagnetic radiation onto the target and measure one or more properties of the scattered electromagnetic radiation (e.g., the intensity of a single reflection angle as a function of wavelength; the intensity of one or more wavelengths as a function of reflection angle; or the polarization as a function of reflection angle) to obtain a diffraction "spectrum" from which a property of interest of the target can be determined.
Conventional binary phase grating marks rely on interference between diffracted light from the top of the line and the bottom of the space. The diffraction of light is highly dependent on the grating depth. The interference between the + and-diffraction orders is detected by the alignment sensor to determine the alignment position. For an ideal mark without any asymmetry, the Alignment Position Deviation (APD) should theoretically be 0. However, due to defects during, for example, etching, Chemical Mechanical Polishing (CMP), deposition, etc., the marks may be deformed in many different ways. Typical marking variations can be simplified and classified into three main asymmetric types, including Floor Tilt (FT), Side Wall Angle (SWA), and Top Tilt (TT). The mark depth may also differ from the nominal value due to the process. When one or more of these asymmetries occur in the printed mark, this will result in an alignment error, i.e., APD. The effect of asymmetry on APD is also highly dependent on mark depth due to the interferometric nature of the phase grating.
The same distortion problem is encountered with overlay targets used to measure overlay error. This may result in inaccurate measured overlay errors.
International patent publication No. WO2019081091a1 (the entire contents of which are incorporated herein by reference) describes these problems and discloses a solution including resonant amplitude markers. Forming a mark on a planar substrate, the mark comprising a periodic structure configured to scatter radiation incident on a surface plane of the alignment mark, the surface plane being parallel to the plane of the substrate, the scattering being primarily due to excitation of resonant modes in the periodic structure parallel to the surface plane. The problem with this approach is that it is limited to design rules based on resonance.
Disclosure of Invention
It is desirable to have marks (typically alignment marks and overlay targets) that are less sensitive to process-induced distortion-induced mark asymmetry within wide design rule tolerances. It is also desirable to provide the following: alignment, overlay measurement, configuring marks used in the alignment and overlay measurement, manufacturing a patterning device comprising the less sensitive marks, and providing the less sensitive marks to a planar substrate. It is also desirable to have a metrology system configured to perform the method of alignment and overlay measurements, and a tool, such as a lithographic apparatus or a standalone metrology tool, comprising the metrology system.
According to a first aspect of the present invention, there is provided an alignment method comprising the steps of: providing an alignment mark formed on or in a planar substrate, the mark comprising a periodic structure, wherein the periodic structure has a repeating unit cell divided along a periodic direction into adjacent first and second portions, the first portion having a first length along the periodic direction and a first effective refractive index, the second portion having a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion within its optical path being lower than the first effective refractive index; illuminating the alignment mark with radiation having a predetermined wavelength, wherein the effective refractive index and length of portions of the alignment mark are configured to provide: a) an optical path length of the unit cell in the periodic direction equal to an integer multiple of the predetermined wavelength, and b) an optical path length or optical path of the second portion in the periodic direction of 0.35 to 0.45 times the predetermined wavelength, such that scattering occurs primarily due to excitation of waveguide modes in the periodic structure; detecting radiation scattered by the alignment marks resulting from the illumination; and determining the position of the alignment mark using the detected radiation.
According to a second aspect of the present invention, there is provided an alignment method comprising the steps of: providing an alignment mark formed on or in a planar substrate, the mark comprising a periodic structure, wherein the periodic structure has a repeating unit cell divided along a periodic direction into adjacent first and second portions, the first portion having a first length along the periodic direction and a first effective refractive index, the second portion having a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion within its optical path being lower than the first effective refractive index; illuminating the alignment mark with broadband radiation comprising a predetermined wavelength, wherein the effective refractive index and the length of portions of the alignment mark are configured to provide: a) an optical path length of the unit cell in the periodic direction equal to an integer multiple of the predetermined wavelength, and b) an optical path length of the second portion in the periodic direction of 0.35 to 0.45 times the predetermined wavelength, such that scattering of the predetermined wavelength occurs primarily due to excitation of waveguide modes in the periodic structure; filtering radiation resulting from the illumination and scattered by the alignment marks to select a wavelength in the periodic structure corresponding to excitation of a waveguide mode parallel to the surface plane; detecting the filtered radiation; and determining the position of the alignment mark using the detected radiation.
According to a third aspect of the present invention, there is provided an overlay measurement method, the method comprising: providing an overlay mark formed on or in a planar substrate, the overlay mark comprising a lower mark superposed with an upper mark, the upper mark having the same pitch as the lower mark, the lower mark comprising a periodic structure, wherein the periodic structure has a repeating unit cell divided along a periodic direction into adjacent first and second portions, the first portion having a first length along the periodic direction and a first effective refractive index, the second portion having a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion within an optical path thereof being lower than the first effective refractive index; illuminating the overlay mark with radiation having a predetermined wavelength, wherein the effective refractive index and length of portions of the underlying mark are configured to provide: a) an optical path length of the unit cell in the periodic direction equal to an integer multiple of the predetermined wavelength, and b) an optical path length of the second portion in the periodic direction in a range of 0.35 to 0.45 times the predetermined wavelength, such that scattering occurs primarily due to excitation of waveguide modes in the periodic structure; detecting radiation resulting from the illumination scattered by the overlapping marks; and determining an overlap at the position of the overlapping mark using the detected radiation.
According to a fourth aspect of the present invention there is provided a method of configuring a mark on or in a planar substrate, the planar substrate having a periodic structure configured to scatter radiation incident on the mark when subjected to alignment or overlay measurements made on the planar substrate, the method comprising: obtaining a wavelength of radiation incident on the mark; and configuring the periodic structure based on excitation of a waveguide mode of the periodic structure that is parallel to a surface plane of the planar substrate when illuminated by incident radiation at the wavelength.
According to a fifth aspect of the present invention, there is provided a method for manufacturing a patterning device for providing a mark comprising a periodic structure to a planar substrate, the method comprising: obtaining a wavelength of radiation used to illuminate the planar substrate when subjected to the alignment or overlay measurement; configuring a periodic structure such that, when provided to a planar substrate: a) scattering incident radiation when subjected to alignment or overlay measurements; and b) coupling incident radiation at said wavelength to a waveguide mode of the periodic structure parallel to the surface plane of the substrate; and providing the configured indicia to the patterning device during a manufacturing process of the patterning device.
According to a sixth aspect of the present invention there is provided a method of providing a mark to a planar substrate, the mark having a periodic structure configured to scatter radiation incident on the mark when subjected to an alignment or overlay measurement, the method comprising: obtaining a patterning device manufactured according to the method of the fifth aspect of the invention; obtaining a planar substrate; and providing a mark to the planar substrate using the patterning device and the planar substrate in a lithographic process.
According to a seventh aspect of the present invention, there is provided a metrology system configured to perform a method according to any one of the first to third aspects of the present invention.
According to an eighth aspect of the invention, there is provided a lithographic apparatus or a metrology tool comprising a metrology system according to the seventh aspect of the invention.
Drawings
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which:
FIG. 1 depicts a schematic overview of a lithographic apparatus;
figure 2 depicts the diffraction of a conventional phase grating;
figure 3 depicts the diffraction of an amplitude grating;
FIG. 4 depicts the grating in a resonant state;
FIG. 5 depicts a Resonant Amplitude Marker (RAM);
FIG. 6 depicts a boot mode flag (GMM) according to an embodiment of the invention;
fig. 7 depicts the field distribution of a single trench for each of four different critical dimensions;
FIG. 8 depicts Wafer Quality (WQ) and Alignment Position Deviation (APD) as a function of alignment mark depth in the presence of 1nm floor tilt angle asymmetry for each of the four different critical dimensions shown in FIG. 7;
FIG. 9 is a flow chart of a method of alignment according to an embodiment of the invention; and
FIG. 10 is a flow chart of a method of overlay error measurement according to an embodiment of the invention.
Detailed Description
FIG. 1 schematically depicts a lithographic apparatus LA. The lithographic apparatus LA comprises: an illumination system (also referred to as an illuminator) IL configured to condition a radiation beam B (e.g. UV radiation, DUV radiation or EUV radiation); a support structure (e.g. a mask table) T configured to support a patterning device (e.g. a mask) MA and connected to a first positioner PM configured to accurately position the patterning device MA in accordance with certain parameters; a substrate table (e.g. a wafer table) WT constructed to hold a substrate (e.g. a resist-coated wafer) W and connected to a second positioner PW configured to accurately position the substrate in accordance with certain parameters; and a projection system (e.g. a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by patterning device MA onto a target portion C (e.g. comprising one or more dies) of the substrate W.
In operation, the illuminator IL receives a radiation beam from a radiation source SO, for example, via a beam delivery system BD. The illumination system IL may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic and/or other types of optical components, or any combination thereof, for directing, shaping, and/or controlling radiation. The illuminator IL may be used to condition the radiation beam B to have a desired spatial and angular intensity distribution in its cross-section at the plane of the patterning device MA.
The term "projection system" PS as used herein should be broadly interpreted as encompassing various types of projection system, including: refractive, reflective, catadioptric, anamorphic, magnetic, electromagnetic and/or electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation being used and/or for other factors such as the use of an immersion liquid or the use of a vacuum. Any use of the term "projection lens" herein may be considered as synonymous with the more general term "projection system" PS.
The lithographic apparatus may be of a type wherein: wherein at least a portion of the substrate may be covered by a liquid having a relatively high refractive index, e.g. water, so as to fill a space between the projection system and the substrate, also referred to as immersion lithography. More information on immersion techniques is given in U.S. Pat. No. 6,952,253 and PCT publication No. WO99-49504, which are incorporated herein by reference.
The lithographic apparatus LA may also be of a type having two (dual stage) or more substrate tables WT and, for example, two or more support structures T (not shown). In such "multiple stage" machines the additional tables/structures may be used in parallel, or preparatory steps may be carried out on one or more tables while one or more other tables are being used for exposing the design layout of the patterning device MA to the substrate W.
In operation, the radiation beam B is incident on the patterning device (e.g., mask MA), which is held on the support structure (e.g., mask table T), and is patterned by the patterning device MA. After traversing the mask MA, the radiation beam B passes through the projection system PS, which focuses the beam onto a target portion C of the substrate W. With the aid of the second positioner PW and position sensor IF (e.g. an interferometric device, linear encoder, 2D encoder or capacitive sensor), the substrate table WT can be moved accurately, e.g. so as to position different target portions C in the path of the radiation beam B. Similarly, the first positioner PM and possibly another position sensor (which is not explicitly depicted in fig. 1) can be used to accurately position the mask MA with respect to the path of the radiation beam B. Mask MA and substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks as illustrated occupy dedicated target portions, they may be located in spaces between target portions (these are known as scribe-lane alignment marks).
Embodiments of the present invention provide a novel mark that is fabricated as a binary grating. A general architecture for an asymmetry insensitive mark design is provided. A general architecture for a mark design that is insensitive to depth variations is also provided. The novel mark design requires only a single wavelength to mitigate the effects of process induced mark asymmetry. Furthermore, the alignment signal strength (wafer quality WQ) can be tuned simply by adjusting the pitch of the marks. The marks simplify the manufacture of reference wafers because the marks are insensitive to process-induced mark asymmetries, thereby providing a "golden" reference wafer for inter-wafer error correction.
Embodiments provide a novel binary mark design that is insensitive to most types of asymmetries (FT, SWA) within a wide design rule tolerance. The binary marker design is insensitive to depth variations and thus to process fluctuations that lead to any asymmetry (FT, SWA, TT).
Before considering the novel labels, a conventional phase grating (fig. 2) will be described, and the principle of amplitude grating (fig. 3) and the principle of generating resonance (fig. 4) will be described in connection with the labels disclosed in WO2019081091a 1.
Fig. 2 depicts diffraction of a conventional phase grating. The periodic structure 210 formed on the planar substrate 212 is irradiated with radiation 200 of wavelength λ, in this example the planar substrate 212 is a grating shown in cross-section. The gaps between the ridges 210 form trenches of depth d extending down to the substrate 212. The (d) is the mark depth. Interference between the scattered radiation 204, 206 reflected at the top and bottom of the grating 210, respectively, helps to generate the scattered radiation 202 for an optimal thickness d. Therefore, diffraction occurs via the modulation of the phase of the reflected wave. The grating introduces a periodic modulation of the wavefront.
Figure 3 depicts diffraction of an amplitude grating. Radiation 300 of wavelength λ illuminates the grating 310. The radiation 302 diffracted by the grating with periodic holes in the reflective film depends only on the period Λ. The reflective film is equivalent to a set of point sources 304. In contrast to phase gratings, diffraction occurs via modulation of the amplitude of the reflected wave, rather than modulation of the phase. Like the phase grating, the amplitude grating introduces a periodic modulation of the wavefront.
Figure 4 depicts the grating in a resonant state. Radiation 400 of wavelength λ illuminates the grating 510. The incident radiation 400 is resonantly excited as a counter propagating wave 408 in the plane of the grating. The grating itself introduces the required momentum.
Fig. 5 depicts a Resonant Amplitude Marker (RAM) according to the disclosure of WO2019081091a 1. Marks are formed on the planar substrate 512. The mark has a periodic structure configured to scatter radiation 502 of wavelength λ incident 500 on a surface plane 506 of the alignment mark. The surface plane 506 is parallel to the plane of the substrate. The scattering is mainly due to excitation of resonant modes 508 in the periodic structure in a plane parallel to the surface.
The periodic structure has a repeating unit cell that is divided into adjacent first and second portions 510, 504 along a periodic direction (left to right in the cross-section of fig. 5).
The first portion 510 has a first length (L) along the periodic directionl) And a first effective refractive index (n)s). The second portion 504 has a second length (L) along the periodic direction2) And a second effective refractive index (n)d) Wherein the second effective refractive index (n) of the second portion in the optical path thereofd) Lower than the first effective index.
Effective refractive index (n) of each portions，nd) And length (L)1，L2) Configured to provide an optical path length (n) of the unit cell in a periodic directionsL1+ndL2) Equal to an integer multiple (m λ) of the wavelengths present or present in the spectrum of the radiation.
The wavelength of the incident radiation may be predetermined such that it matches the resonant design rules. Alternatively, broadband radiation may be incident on the marker, and the alignment sensor frequency filter may then be tuned to select the resonant mode wavelength.
Effective refractive index (n) of each portions，nd) And length (L)1，L2) Is also configured to provide an optical path length (n) of the second portion in the periodic directiondL2) Equal to half an integer multiple of the wavelengths present in the radiation spectrum (k λ/2). These are conditions that match the wavelength of the radiation to the grating material boundary conditions to support resonance.
In this example, the optical path length of the second portion in the periodic direction (n)dL2) Equal to half the wavelength present in the spectrum of the radiation (λ/2), so that only one antinode of the resonant mode is present in the second part 504, i.e. k is 1. When k is>1, there are odd number of antinodes, but even number of antinodes cancel each other out leaving only one antinode contributing to scattering, but the efficiency is reduced.
Forming marks, e.g. P in FIG. 1, on a planar substrate, e.g. a wafer W1And P2As depicted.
The radiation diffracted by the marks does not contain information about the mark profile but only information about the position of the marks on the wafer. The marker may be referred to as a Resonant Amplitude Marker (RAM). The terms are chosen to emphasize the different working principles of such a RAM with respect to conventional alignment marks based on phase gratings (as described with reference to fig. 2). "Mark" and "grating" may be used interchangeably. The grating may be a one-dimensional (1-D) grating, as described with reference to the example of fig. 5, but the invention is not limited to 1-D gratings. The invention can be applied to 2-D gratings, which have an effective index of refraction and length in two periodic directions configured to support resonance.
In this marker design, radiation from the alignment sensor excites two counter-propagating waves in the grating plane. These two waveforms form a so-called "standing wave", i.e. a resonant mode in the plane of the grating. As described with reference to fig. 4, the two counter-propagating waves do not propagate throughout the depth of the mark, but stay on the surface of the mark and are therefore not affected by the depth of the mark.
This resonant mode effectively leaks light to the grating stage, as any other type of marker, and can be captured in much the same way as a conventional marker, thus eliminating the need for new sensor designs. In fact, the sensor will not be able to distinguish whether the light is coming from the RAM or the conventional mark, which has the advantage that the light coming from the RAM does not contain information about the mark profile, but only about the mark position, because the resonance mode is located in the grating plane. In fact, in case the light diffracted in the grating order (the radiation properties of which do not depend on the mark depth) comes from a point source positioned in a periodic manner on the grating surface, the mark appears as an amplitude mark. This is similar to the case of periodic slits opened in a reflective opaque film, as described with reference to fig. 3.
By appropriate design, this makes the label less sensitive to the presence of the layer stacked below it, and the label can also be used as an overlay target (see fig. 17 of WO 2019081091A) or in label stacking (see fig. 16 of W02019081091A).
For RAM configurations, it is desirable to efficiently couple to the resonant modes and efficiently leak the modes into the sensor plane.
These are provided by using the following design rules:
the optical path of the grating unit cell is equal to an integer multiple of the wavelength:
nSL1+ndL2＝mλ (1)
and the optical path of the low refractive index material (space) is equal to half the wavelength:
ndL2＝kλ/2, (2)
wherein L is1+L2Λ (pitch) and k is an integer, preferably, k is 1. According to these two simple design rules, different pitches can be used for specific colors according to the sensor specifications (numerical aperture, NA). Thus, for a fixed wavelength λ, an increase in the mark pitch Λ will result in a larger duty cycle.
In embodiments of the present invention, diffraction similarly occurs primarily at the grating top interface, and little light is diffracted from the grating bottom interface. Fig. 6 depicts a Guided Mode Marker (GMM) as a one-dimensional photonic crystal used to define a nominal design rule.
Referring to FIG. 6, the k vector in air in the x direction is
The k vector in silicon along the x direction is
The period of the 1D photonic crystal is
d＝d1+d2。
The dispersion relation of the 1D photonic crystal is
By k x0 and
to solve for eigenmodes
We get nominal design rules:
next, we change the nomenclature to match the nomenclature of equations (1) and (2).
In the portion with the lower effective refractive index (e.g., air):
will d2Is changed into L2And n is2Is changed into nd。
In the portion having a higher effective refractive index (e.g., Si):
will d1Is changed into L1And n is1Is changed into ns。
Thus, we will equate λ with λ (italics), and m with m (italics),
will be provided with
And
become into
therefore, the temperature of the molten metal is controlled,
this is the same design rule as equation (2).
In addition to this, the present invention is,
will be provided with
Addition to both sides:
nsLl+ndL2＝mλ；m＝1，2，3…
this is the same design rule as equation (1). Thus, the waveguide theoretical architecture results in the same nominal design rules (equations (3) and (4)) as the resonant mode approach (equations (1) and (2)) disclosed in WO2019081091a 1. However, the use of waveguide theory shows that the design rules for such marks are no longer limited to nominal design rules based on resonance.
FIG. 6 depicts a boot mode flag (GMM) according to an embodiment of the present invention. Marks are formed on the planar substrate 612. The marks have a periodic structure configured to scatter radiation 602 of wavelength λ incident 600 on the alignment marks. Scattering is mainly due to coupling of incident radiation into waveguide modes in the periodic structure.
The periodic structure has a repeating unit cell divided into adjacent first and second portions 610 and 604 along a periodic direction (x direction in the cross-section of fig. 6; left to right).
The first portion 610 has a first length (d) along the periodic directionl) And a first effective refractive index (n)l). The second portion 604 has a second length (d) along the periodic direction2) And a second effective refractive index (n)2) Wherein the second effective refractive index (n) of the second portion in the optical path thereof2) Lower than the first effective index.
Effective refractive index (n) of each portionl，n2) And length (d)l，d2) Configured to provide an optical path length (n) of the unit cell in a periodic direction1d1+n1d1) Equal to an integer multiple of the wavelengths present in the radiation spectrum (m λ).
The wavelength of the incident radiation can be predetermined such that it matches the waveguide theoretical design rules. Alternatively, broadband radiation may be incident on the marker, and the alignment sensor frequency filter may then be tuned to select the wavelength associated with the desired waveguide mode.
Effective refractive index (n) of each portionl，n2) And length (d)l，d2) Is also configured to provide an optical path length (n) of the second portion in the periodic direction2d2) Preferably equal to 0.30 to 0.49 (more preferably 0.35 to 0.45) times the wavelength present in the spectrum of the radiation. These are conditions that match the wavelength of the radiation to the grating material boundary conditions to support the generation of waveguide modes.
Forming marks, e.g. P in FIG. 1, on a planar substrate, e.g. a wafer W1And P2As depicted.
The radiation diffracted by the marks does not contain information about the mark profile but only information about the position of the marks on the wafer. The flag may be referred to as a steering mode flag (GMM). The terms are chosen to emphasize the different working principles of this GMM with respect to conventional alignment marks based on phase gratings (as described with reference to fig. 2) and the RAM described with reference to fig. 5. "Mark" and "grating" may be used interchangeably. The grating may be a one-dimensional (1-D) grating, as described with reference to the example of fig. 6, but the invention is not limited to 1-D gratings. The invention can be applied to 2-D gratings, which have an effective index of refraction and length in two periodic directions configured to support resonance.
By appropriate design, this makes the label less sensitive to the presence of the layer stacked below it, and the label can also be used as an overlay target (see fig. 17 of WO 2019081091A) or in label stacking (see fig. 16 of W02019081091A).
Once the nominal design rule is met, light will be predominantly coupled into the waveguide modes, which are predominantly confined and propagating within the silicon ridges and evanescently coupled through the silicon ridges adjacent to the silicon ridges by the trenches (see field distribution in fig. 7 where CD is the width of the air trench). Therefore, FT will have minimal impact on the APD. SWA only slightly affects the guiding mode in case of impractically large mark depths. TT is located at the grating top interface, which will affect the coupling of light into the waveguide mode, mainly as a general offset. Since diffraction occurs primarily at the grating top interface in all three types of asymmetry, the APD's dependence on mark depth due to asymmetry is small compared to conventional mark types.
Surprisingly, however, using the waveguide theoretical architecture, we also observed smaller APDs in the simulations for the case of CD 0.4 x λ. We can see from the field distribution that light can still be coupled into the waveguide mode, but not as much as in the case of CD 0.5 x λ. This indicates that the design rules disclosed in WO2019081091a1 and represented by equations (1) to (4) need not be exactly satisfied. In this case, a very small portion of the light will propagate in the trench, but with a small effective mode index. Due to the small effective mode index, the geometric asymmetry will introduce less phase asymmetry. Small effective mode index effects result in small APDs.
Another effect of small APDs, which also contributes to FT, is the small CD effect. In this mark type, the duty cycle (space: baseline) is less than 50%. Thus, the same degree of mark asymmetry will result in a smaller shift in the center of gravity of the mark. This effect applies to both s-and p-polarization.
Fig. 7 depicts the field distribution of a single trench for each of four different Critical Dimensions (CDs), where CD is the width of the air trench. "-" indicates the negative value of the electric field. "+" represents a positive value of the electric field. On both sides of and below the trench, the black pattern represents alternating negative and positive electric field values in the silicon.
FIG. 8 depicts Wafer Quality (WQ) and Alignment Position Deviation (APD) as a function of alignment mark depth d (from 0.2 λ to 2 λ) in the presence of 1nm floor tilt angle asymmetry for each of the four different critical dimensions shown in FIG. 7. WQ is the alignment signal strength.
The results of the following table can be obtained from fig. 8.
The representation shows that within a wide tolerance of CD the mark is insensitive to mark depth, since (for a mark depth range from 0.2 λ to 2 λ) at typical FT values of 1nm, this leads to a smaller analog APD variation for both CD-0.5 λ and CD-0.4 λ.
FIG. 9 is a flow chart of a method of alignment according to an embodiment of the present invention. The method of alignment has the following steps.
902 (MRK): an alignment mark formed on a planar substrate is provided.
904 (ILL): the alignment marks are irradiated with radiation of a predetermined wavelength.
906 (DET): radiation scattered by the alignment marks resulting from the illumination is detected.
908 (APD): the position of the alignment mark (APD) is determined using the detected radiation.
The alignment mark has a periodic structure configured to scatter radiation incident on the alignment mark. Scattering is mainly due to coupling of incident radiation into waveguide modes in the periodic structure.
FIG. 10 is a flow chart of a method of overlay error measurement according to an embodiment of the invention. The method of determining the overlay error has the following steps.
1002 (TGT): an overlay target formed on a planar substrate is provided. The overlay target has a lower mark that overlaps an upper mark having the same pitch as the lower mark. The lower mark has a periodic structure configured to scatter radiation incident on a surface plane of the lower mark. The surface plane is parallel to the substrate plane. Scattering is mainly due to coupling of incident radiation into the waveguide mode. The upper mark has a periodic structure: the periodic structure is configured to scatter radiation of a predetermined wavelength, but the scattering is not primarily due to coupling of incident radiation into waveguide modes in the periodic structure of the upper marker.
1004 (ILL): the overlay target is illuminated with radiation of a predetermined wavelength.
1006 (DET): radiation scattered by the overlapping objects resulting from the illumination is detected.
1008 (OV): the detected radiation is used to determine the overlay error OV between the upper and lower marks.
Referring to fig. 9 and 10, the periodic structure has a repeating unit cell divided into adjacent first and second portions in a periodic direction. The first portion has a first length along the periodic direction and a first effective index of refraction. The second portion has a second length along the periodic direction and a second effective refractive index, wherein the second effective refractive index of the second portion in its optical path is lower than the first effective refractive index. The effective refractive index and length of each portion are configured to provide an optical path length of the unit cell in the periodic direction that is equal to an integer multiple of a wavelength present in the radiation spectrum. The effective refractive index and length of each portion is configured to provide an optical path length of the second portion in the periodic direction that is preferably equal to 0.30 to 0.49 (more preferably 0.35 to 0.45) times the wavelength present in the spectrum.
Embodiments of the present invention have several advantages over the disclosure of WO2019081091a1 within a wider design rule tolerance.
The alignment and overlay measurement methods are less complex; for alignment purposes only a single wavelength is required because for GMM, within a wide tolerance, the WQ and APD do not vary as a function of mark depth.
The alignment and overlay measurement methods are more accurate; in the case of process-induced asymmetries, especially FT, the APDs obtained are very small for GMM; for typical values of FT ═ 1nm, the APD is less than 0.5 angstroms, within a wide tolerance.
Within a wide tolerance, the alignment and overlay measurement method is faster, especially if only one color of tunable light source can be provided at a time.
The marks and targets can be used for golden reference wafers for inter-wafer error correction because, within a wide tolerance, they are not sensitive to asymmetry.
There are improvements in copper dual damascene type structures; the presence of layers below the GMM mark has a limited effect on the signal, thus allowing a more stable APD or OV readout to be achieved within a wider tolerance.
Similar to that described with reference to fig. 17 of WO2019081091a1, the GMM may be used as a bottom grating of an overlay target to reduce the effect of layers under the marks affecting the overlay readout signal within a wide tolerance.
Furthermore, embodiments of the present invention are compatible with smaller marks within a wider tolerance.
Embodiments provide sub-angstrom grade APDs with FT ═ 1 nm.
The examples provide sub-nanoscale APDs for practical mark depth ranges [0.1-1 λ ], with SWA ═ 1 degrees.
Embodiments are insensitive to mark depth, (e.g., with APD variation of 0.08nm for FT and 0.4nm for SWA), thus favoring higher etch/polish/deposition tolerances for lithographic processing tools.
Further embodiments provide methods of configuring a mark for use in alignment and/or overlay measurement, for example, methods applied to a process of designing a mark. The design/configuration of the markers is intended to obtain excitation of the desired waveguide mode when illuminated by radiation having a specific wavelength. In a first step, the marker is configured by using a computer program and a computer system adapted to provide a design of said marker such that the marker follows design rules associated with excitation of a desired waveguide mode. In a second step, a patterning device is manufactured, the patterning device comprising at least one marking that is compatible with the design rule. In a third step, the (planar) substrate is provided with marks by exposing the patterning device obtained by the manufacturing to a planar substrate using any suitable lithographic process. Typically, the patterning device is then loaded into the lithographic apparatus, and the planar substrate is provided with a photosensitive layer (resist coating) and then loaded into the lithographic apparatus. After exposing the patterning device to the coated planar substrate and developing the resist, the marks are provided to the substrate. Subsequently, an etching process may be applied to etch the marker pattern into the planar substrate material.
Further, the metrology system may be configured to perform the method of alignment and/or overlay measurement as depicted in fig. 9 and 10. The metrology system may be an alignment or overlay measurement system within a lithographic apparatus or a metrology tool (such as an integrated or standalone scatterometry tool). The metrology system is configured to provide radiation of a wavelength suitable for exciting a waveguide mode associated with a mark provided to the planar substrate.
Other embodiments are disclosed in the following numbered list:
1. a method of performing alignment or overlay measurements on a mark, the mark comprising a periodic structure, the mark being formed on or in a planar substrate, the method comprising:
illuminating the mark with radiation having a predetermined wavelength;
detecting radiation scattered by the label resulting from the illumination; and
the detected radiation is used to determine a position or overlap value,
characterized in that the predetermined wavelength and the periodic structure are configured to provide scattering of the radiation by excitation of a waveguide mode in the periodic structure parallel to a surface plane of the planar substrate.
2. The method of aspect 1, wherein the periodic structure has a repeating unit cell divided into adjacent first and second portions along a periodic direction, wherein:
the first portion has a first length along the periodic direction and a first effective index of refraction;
a second portion having a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion in its optical path being lower than the first effective refractive index;
the optical path length of the unit cell in the periodic direction is equal to or close to an integer multiple of the predetermined wavelength; and is
The optical path length of the second portion in the periodic direction is in the range of 0.35 to 0.45 times the predetermined wavelength.
3. The method of aspect 1 or 2, wherein detecting comprises: a) filtering radiation scattered by the marker to select only scattered radiation having a wavelength close to or equal to a predetermined wavelength; and b) detecting the filtered radiation.
4. The method according to any one of the preceding aspects, wherein the mark is a lower mark of an overlay mark, the overlay mark being composed of the lower mark superposed with an upper mark, the upper mark having the same pitch as the lower mark.
5. A method of alignment, the method comprising the steps of:
providing an alignment mark formed on or in a planar substrate, the mark comprising a periodic structure, wherein the periodic structure has a repeating unit cell divided in a periodic direction into adjacent first and second portions, the first portion having a first length and a first effective refractive index in the periodic direction, the second portion having a second length and a second effective refractive index in the periodic direction, the second effective refractive index of the second portion in its optical path range being lower than the first effective refractive index, and
illuminating the alignment mark with radiation having a predetermined wavelength, wherein the effective refractive index and length of portions of the alignment mark are configured to provide: a) an optical path length of the unit cell in the periodic direction equal to an integer multiple of the predetermined wavelength, and b) an optical path length of the second portion in the periodic direction of 0.35 to 0.45 times the predetermined wavelength, such that scattering occurs primarily due to excitation of waveguide modes in the periodic structure;
detecting radiation scattered by the alignment marks resulting from the illumination; and
the position of the alignment mark is determined using the detected radiation.
6. A method of alignment, the method comprising the steps of:
providing an alignment mark formed on or in a planar substrate, the mark comprising a periodic structure, wherein the periodic structure has a repeating unit cell divided along a periodic direction into adjacent first and second portions, the first portion having a first length along the periodic direction and a first effective refractive index, the second portion having a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion within its optical path being lower than the first effective refractive index;
illuminating the alignment mark with broadband radiation comprising a predetermined wavelength, wherein the effective refractive index and the length of portions of the alignment mark are configured to provide: a) an optical path length of the unit cell in the periodic direction equal to an integer multiple of the predetermined wavelength, and b) an optical path length of the second portion in the periodic direction of 0.35 to 0.45 times the predetermined wavelength, such that scattering of the predetermined wavelength occurs primarily due to excitation of waveguide modes in the periodic structure;
filtering radiation resulting from the illumination and scattered by the alignment marks to select a wavelength in the periodic structure corresponding to excitation of a waveguide mode parallel to the surface plane;
detecting the filtered radiation; and
the position of the alignment mark is determined using the detected radiation.
7. An overlay measurement method, the method comprising:
providing an overlay mark formed on or in a planar substrate, the overlay mark comprising a lower mark superposed with an upper mark, the upper mark having the same pitch as the lower mark, the lower mark comprising a periodic structure, wherein the periodic structure has a repeating unit cell divided along a periodic direction into adjacent first and second portions, the first portion having a first length along the periodic direction and a first effective refractive index, the second portion having a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion within an optical path thereof being lower than the first effective refractive index;
illuminating the overlapping marks with radiation having a predetermined wavelength, wherein the effective refractive index and length of the portion of the lower mark are configured to provide: a) an optical path length of the unit cell in the periodic direction equal to an integer multiple of the predetermined wavelength, and b) an optical path length of the second portion in the periodic direction in a range of 0.35 to 0.45 times the predetermined wavelength, such that scattering occurs primarily due to excitation of waveguide modes in the periodic structure;
detecting radiation resulting from the illumination scattered by the overlapping marks; and
the detected radiation is used to determine the overlap at the position of the overlapping marks.
8. A method of configuring a marker on or in a planar substrate having a periodic structure configured to scatter radiation incident on the marker when subjected to alignment or overlay measurements made on the planar substrate, the method comprising:
obtaining a wavelength of radiation incident on the mark; and
the periodic structure is configured based on the occurrence of a waveguide mode parallel to the surface plane of the planar substrate that couples incident radiation to the periodic structure.
9. The method of aspect 8, wherein:
the periodic structure has a repeating unit cell divided into adjacent first and second portions along the periodic direction, wherein the first portion has a first length and a first effective refractive index along the periodic direction, and the second portion has a second length and a second effective refractive index along the periodic direction, the second effective refractive index of the second portion within an optical path thereof being lower than the first effective refractive index; and is
The configuration of the periodic structure is based on the following arrangement: a) the optical path length of the unit cell in the periodic direction is equal to an integer multiple of the wavelength, and b) the optical path length of the second section in the periodic direction is in the range of 0.30 to 0.45 times the wavelength.
10. A method for manufacturing a patterning device for providing a planar substrate with a mark comprising a periodic structure, the method comprising:
obtaining a wavelength of radiation used to illuminate the planar substrate when subjected to the alignment or overlay measurement;
configuring a periodic structure such that, when provided to a planar substrate:
a) scattering incident radiation when subjected to alignment or overlay measurements; and is
b) Coupling incident radiation at the wavelength to a waveguide mode of the periodic structure parallel to a surface plane of the substrate; and
the configured indicia is provided to the patterning device during a manufacturing process of the patterning device.
11. A method of providing a planar substrate with a mark having a periodic structure configured to scatter radiation incident on the mark when subjected to an alignment or overlay measurement, the method comprising:
obtaining a patterning device manufactured according to the method of aspect 10;
obtaining a planar substrate; and
the patterning device and the planar substrate are used in a lithographic process to provide marks to the planar substrate.
12. A metrology system configured to perform the method of any one of aspects 1-7.
13. A lithographic apparatus or a metrology tool comprising a metrology system according to aspect 12.
14. A computer program comprising instructions for performing the method according to any one of aspects 1 to 11.
15. A computer system configured to execute the computer program according to aspect 14.
16. A mark formed on a planar substrate, the mark comprising a periodic structure configured to scatter radiation incident on an alignment mark, the scattering resulting primarily from coupling the incident radiation into a waveguide mode in the periodic structure, wherein the periodic structure has a repeating unit cell divided into adjacent first and second portions along a periodic direction,
the first portion has a first length along the periodic direction and the first effective refractive index,
the second portion has a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion in its optical path being lower than the first effective refractive index,
wherein the effective refractive index and length of each portion are configured to provide:
1) the unit cell has an optical path length in the periodic direction equal to an integer multiple of a wavelength present in the spectrum of the radiation, an
2) The second portion has an optical path length in the periodic direction of 0.30 to 0.49 times a wavelength present in the spectrum of the radiation.
17. The marker of aspect 16, wherein the effective refractive index and the length of each portion are configured to provide: an optical path length of the second portion in the periodic direction of between 0.35 and 0.45 times a wavelength present in the spectrum of the radiation.
18. A substrate comprising the marking of aspect 16 or aspect 17.
19. An overlay target comprising a lower mark according to aspect 16 or aspect 17, the lower mark overlying an upper mark, the upper mark having the same pitch as the lower mark, and the lower mark comprising a periodic structure configured to scatter radiation, the scattering not being primarily caused by coupling of incident radiation into a waveguide mode in its periodic structure.
20. A substrate comprising the overlay target of aspect 19.
21. An alignment method, comprising the steps of:
-providing an alignment mark formed on a planar substrate according to the mark of aspect 16 or aspect 17;
-illuminating the alignment mark with radiation;
-detecting radiation resulting from the illumination scattered by the alignment marks; and
-using the detected radiation to determine the position of the alignment mark.
22. A method of determining an overlay error, the method comprising the steps of:
providing an overlay target formed on a planar substrate, the overlay target comprising a lower mark superposed with an upper mark, the upper mark having the same pitch as the lower mark,
wherein:
-the lower indicia comprises indicia according to aspect 16 or aspect 17; and is
-the upper marker comprises a periodic structure configured to scatter radiation, but the scattering is not mainly due to coupling of incident radiation into waveguide modes in its periodic structure;
-illuminating the overlapping targets with radiation;
-detecting radiation scattered by the overlapping targets resulting from the illumination; and
-using the detected radiation to determine an overlay error between the upper mark and the lower mark.
Although specific reference may be made in this text to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein may have other applications, such as the processing of substrates in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat-panel displays, liquid-crystal displays (LCDs), thin-film magnetic heads, etc. The skilled artisan will appreciate that, in the context of such alternative applications, any use of the terms "wafer" or "field"/"die" herein may be considered as synonymous with the more general terms "substrate" or "target portion", respectively. The substrate referred to herein may be processed, before or after exposure, in for example a track or a coating and developing system (a tool that typically applies a layer of resist to a substrate and develops the exposed resist), a metrology tool and/or an inspection tool. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Further, the substrate may be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein may also refer to a substrate that already contains multiple processed layers.
Although specific reference may have been made above to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that the invention may be used in other applications, for example imprint lithography, and where the context allows, is not limited to lithography. In imprint lithography, a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device may be pressed into a layer of resist provided to the substrate and the resist on the substrate is then cured by applying electromagnetic radiation, heat, pressure or a combination thereof. After the resist is cured, the patterning device is moved out of the resist, leaving a pattern in the resist.
The terms "radiation" and "beam" used herein encompass all types of electromagnetic radiation, including Ultraviolet (UV) radiation (e.g. having a wavelength of or about 365nm, 248nm, 193nm, 157nm or 126 nm) and extreme ultra-violet (EUV) radiation (e.g. having a wavelength in the range of 5nm-20 nm), as well as particle beams, such as ion beams or electron beams.
The term "lens", where the context allows, may refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic and electrostatic optical components.
While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, the invention may take the form of a computer program containing one or more sequences of machine-readable instructions describing a method as disclosed above, or a data storage medium (e.g. semiconductor memory, magnetic or optical disk) having such a computer program stored therein.
The above description is intended to be illustrative, and not restrictive. Thus, it will be apparent to those skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below. In addition, it should be appreciated that structural features or method steps shown or described in any embodiment herein may also be used in other embodiments.
Claims (9)
1. A method of alignment, the method comprising the steps of:
providing an alignment mark formed on or in a planar substrate, the mark comprising a periodic structure, wherein the periodic structure has a repeating unit cell divided along a periodic direction into adjacent first and second portions, the first portion having a first length along the periodic direction and a first effective refractive index, the second portion having a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion within its optical path being lower than the first effective refractive index;
illuminating the alignment mark with radiation having a predetermined wavelength, wherein the effective refractive index and length of portions of the alignment mark are configured to provide: a) an optical path length of the unit cell in the periodic direction equal to an integer multiple of the predetermined wavelength, and b) an optical path length of the second portion in the periodic direction of 0.35 to 0.45 times the predetermined wavelength, such that scattering occurs primarily due to excitation of waveguide modes in the periodic structure;
detecting radiation scattered by the alignment marks resulting from the illumination; and
determining a position of the alignment mark using the detected radiation.
2. A method of alignment, the method comprising the steps of:
providing an alignment mark formed on or in a planar substrate, the mark comprising a periodic structure, wherein the periodic structure has a repeating unit cell divided along a periodic direction into adjacent first and second portions, the first portion having a first length along the periodic direction and a first effective refractive index, the second portion having a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion within its optical path being lower than the first effective refractive index;
illuminating the alignment mark with broadband radiation comprising a predetermined wavelength, wherein the effective refractive index and length of portions of the alignment mark are configured to provide: a) an optical path length of the unit cell in the periodic direction equal to an integer multiple of the predetermined wavelength, and b) an optical path length of the second portion in the periodic direction of 0.35 to 0.45 times the predetermined wavelength, such that scattering of the predetermined wavelength occurs primarily due to excitation of waveguide modes in the periodic structure;
filtering radiation scattered by the alignment marks resulting from the illumination to select a wavelength corresponding to excitation of a waveguide mode in the periodic structure parallel to a surface plane;
detecting the filtered radiation; and
determining a position of the alignment mark using the detected radiation.
3. An overlay measurement method, the method comprising:
providing an overlay mark formed on or in a planar substrate, the overlay mark comprising a lower mark superposed with an upper mark, the upper mark having the same pitch as the lower mark, the lower mark comprising a periodic structure, wherein the periodic structure has a repeating unit cell divided along a periodic direction into adjacent first and second portions, the first portion having a first length along the periodic direction and a first effective refractive index, the second portion having a second length along the periodic direction and a second effective refractive index, the second effective refractive index of the second portion within its optical path being lower than the first effective refractive index;
illuminating the overlapping mark with radiation having a predetermined wavelength, wherein the effective refractive index and length of portions of the underlying mark are configured to provide: a) an optical path length of the unit cell in the periodic direction equal to an integer multiple of the predetermined wavelength, and b) an optical path length of the second portion in the periodic direction in a range of 0.35 to 0.45 times the predetermined wavelength, such that scattering occurs primarily due to excitation of waveguide modes in the periodic structure;
detecting radiation resulting from the illumination scattered by the overlay marks; and
determining an overlap at the position of the overlapping mark using the detected radiation.
4. A method of configuring a marker on or in a planar substrate, the marker having a periodic structure configured to scatter radiation incident on the marker when subjected to alignment or overlay measurements made on the planar substrate, the method comprising:
obtaining a wavelength of radiation incident on the mark; and
configuring the periodic structure based on excitation of a waveguide mode of the periodic structure that is parallel to a surface plane of the planar substrate when illuminated by incident radiation at the wavelength.
5. The method of claim 4, wherein:
the periodic structure has a repeating unit cell divided into adjacent first and second portions along a periodic direction, wherein the first portion has a first length and a first effective refractive index along the periodic direction, and the second portion has a second length and a second effective refractive index along the periodic direction, the second effective refractive index of the second portion within an optical path thereof being lower than the first effective refractive index; and is
The configuration of the periodic structure is based on the following arrangement: a) an optical path length of the unit cell in the periodic direction is equal to an integral multiple of the wavelength, and b) an optical path length of the second section in the periodic direction is in a range of 0.30 to 0.45 times the wavelength.
6. A method for manufacturing a patterning device used to provide a planar substrate with a mark comprising a periodic structure, the method comprising:
obtaining a wavelength of radiation used to illuminate the planar substrate when subjected to alignment or overlay measurements;
configuring the periodic structure such that, when provided to the planar substrate:
a) scattering incident radiation while being subjected to the alignment or the overlay measurement; and is
b) Coupling incident radiation at the wavelength to a waveguide mode of the periodic structure parallel to a surface plane of the substrate; and
providing the configured indicia to the patterning device during a manufacturing process of the patterning device.
7. A method for providing a mark to a planar substrate, the mark having a periodic structure configured to scatter radiation incident on the mark when subjected to an alignment or overlay measurement, the method comprising:
obtaining a patterning device manufactured according to the method of claim 6;
obtaining the planar substrate; and
using the patterning device and the planar substrate in a lithographic process to provide the indicia to the planar substrate.
8. A metrology system configured to perform the method of any one of claims 1 to 3.
9. A lithographic apparatus or metrology tool comprising the metrology system of claim 8.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP19186248.1 | 2019-07-15 | ||
| EP19186248 | 2019-07-15 | ||
| EP19186925.4A EP3767394A1 (en) | 2019-07-18 | 2019-07-18 | Mark, overlay target, and methods of alignment and overlay |
| EP19186925.4 | 2019-07-18 | ||
| PCT/EP2020/066478 WO2021008794A1 (en) | 2019-07-15 | 2020-06-15 | Methods of alignment, overlay, configuration of marks, manufacturing of patterning devices and patterning the marks |
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| CN114008540A true CN114008540A (en) | 2022-02-01 |
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| CN202080045170.5A Pending CN114008540A (en) | 2019-07-15 | 2020-06-15 | Alignment, overlay, alignment mark, method of manufacturing pattern forming apparatus, and method of manufacturing pattern mark |
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| US (1) | US11675281B2 (en) |
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| US11854854B2 (en) * | 2021-07-23 | 2023-12-26 | Taiwan Semiconductor Manufacturing Company, Ltd. | Method for calibrating alignment of wafer and lithography system |
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|---|---|---|---|---|
| EP1788451A1 (en) * | 2005-11-22 | 2007-05-23 | ASML Netherlands B.V. | Binary sinusoidal sub-wavelength gratings as alignment marks |
| CN101029949A (en) * | 2006-02-28 | 2007-09-05 | 佳能株式会社 | Optical element and method of manufacturing optical element |
| CN101251617A (en) * | 2007-02-20 | 2008-08-27 | 精工爱普生株式会社 | Method for manufacturing micro architecture body |
| US20090310113A1 (en) * | 2008-06-11 | 2009-12-17 | Asml Netherlands B.V. | Sub-segmented alignment mark arrangement |
| WO2019081091A1 (en) * | 2017-10-24 | 2019-05-02 | Asml Netherlands B.V. | Mark, overlay target, and methods of alignment and overlay |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2747999A (en) | 1998-03-26 | 1999-10-18 | Nikon Corporation | Projection exposure method and system |
| SG135052A1 (en) | 2002-11-12 | 2007-09-28 | Asml Netherlands Bv | Lithographic apparatus and device manufacturing method |
| US7791727B2 (en) | 2004-08-16 | 2010-09-07 | Asml Netherlands B.V. | Method and apparatus for angular-resolved spectroscopic lithography characterization |
-
2020
- 2020-06-15 WO PCT/EP2020/066478 patent/WO2021008794A1/en active Application Filing
- 2020-06-15 CN CN202080045170.5A patent/CN114008540A/en active Pending
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1788451A1 (en) * | 2005-11-22 | 2007-05-23 | ASML Netherlands B.V. | Binary sinusoidal sub-wavelength gratings as alignment marks |
| CN101029949A (en) * | 2006-02-28 | 2007-09-05 | 佳能株式会社 | Optical element and method of manufacturing optical element |
| CN101251617A (en) * | 2007-02-20 | 2008-08-27 | 精工爱普生株式会社 | Method for manufacturing micro architecture body |
| US20090310113A1 (en) * | 2008-06-11 | 2009-12-17 | Asml Netherlands B.V. | Sub-segmented alignment mark arrangement |
| WO2019081091A1 (en) * | 2017-10-24 | 2019-05-02 | Asml Netherlands B.V. | Mark, overlay target, and methods of alignment and overlay |
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| US11675281B2 (en) | 2023-06-13 |
| WO2021008794A1 (en) | 2021-01-21 |
| US20220252994A1 (en) | 2022-08-11 |
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